Tag Archives: ocean noise

“Sonic Sea,” which will air Thursday on Discovery Channel, will
take you down beneath the ocean waves, where sounds take on new
meaning, some with dangerous implications.

Humans spend most of their time in air, a medium that transmits
light so well that we have no trouble seeing the shapes of objects
in a room or mountains many miles away. In the same way, water is
the right medium for sound, which shapes the world of marine
mammals and other species that live under water.

The hour-long documentary film reveals how humpback whales use
low-frequency sounds to communicate with other whales across an
entire ocean and how killer whales use high-frequency sound to
locate their prey in dark waters.

Michael Jasny

“The whales see the ocean through sound, so their mind’s eye is
their mind’s ear,” says Michael Jasny of the Natural Resources
Defense Council, an environment group that produced the film with
the help of the production company Imaginary Forces.

“Sonic Sea” opens with Ken Balcomb, dean of killer whale
research in Puget Sound, telling the story of how he learned about
16 beaked whales that had beached themselves in the Bahamas, where
he was doing research in 2001.

“Animals that I had grown to know over a 10-year period were now
dead,” Ken says during the movie, recalling the horrifying day when
one whale after another was discovered dead or dying. “They were
trying to get away. I was driven to find out why.”

Ken Balcomb

Thanks to Ken’s presence during that stranding incident, experts
were able to prove that Navy sonar could be deadly. It took two
years for Navy officials to overcome their denial.

As I watched the film, I wondered if people would identify with
the idea that hearing to marine mammals is like sight to humans.
Would people see how much humans have invaded the underwater world
with noise from ship traffic, oil exploration, military training
and shoreline construction?

“I listen to the world, and to me song is life,” said Chris
Clark, a bioacoustics expert at Cornell Lab of Ornithology,. “It is
the essence of who we are, and it joins us all. The problem is, in
the ocean, we are injecting enormous amounts of noise, so much so
that we are acoustically bleaching the ocean. All the singing
voices of the planet are lost in that cloud of noise.”

Chris Clark

This type of human invasion is different from wiping out habitat
as new construction changes the land, but the effect can be equally
devastating to some species.

In September of 2001, a group of researchers on the East Coast
were collecting fecal samples from right whales to check for stress
hormones. Stress levels were running high among the whales, except
for a few days when the levels dropped dramatically. That happened
right after Sept. 11, when ship traffic in the area was shut down
following the bombing of the World Trade Center. It still isn’t
clear what that constant stress is doing to the animals, but it
can’t be good. See
Duke University press release.

The good news, the film tells us, is that ships can be made
quieter, with an important side benefit: Quieter ships are more
efficient, which makes them cheaper to operate. Ships can also
reduce noise by going slower, saving on fuel. Beyond shipping,
people can find ways to operate in the ocean with less sonic harm
to sea life.

The Navy’s viewpoint, as represented in the film, appears to be
a more enlightened approach that I have seen until now. Of course,
protecting Navy ships against enemy attacks is the priority, but
the need to accommodate marine life seems to be recognized to a
greater degree.

“It comes down to what we value,” Clark said. “We value a living
ocean. We are putting the ocean at risk. And if you put the ocean
at risk, you are putting all of us at risk.”

The first video on this page is the trailer to “Sonic Sea” as
provided by the producers of the film. The second is the trailer
provided by Discovery Channel.

In the underwater world, where hearing can be more important
than sight, whales are being bombarded by a cacophony of sounds,
which started cluttering up their lives when the first steamships
were launched into the ocean.

J-1, known as “Ruffles,” uses
echolocation clicks to locate chinook salmon as a tanker approaches
in Haro Strait near the San Juan Islands. J-1 was the oldest male
among the Southern Resident killer whales when he died in 2011. //
Photo: beamreach.org

Now, after 200 years, people are beginning to care about the
kinds of noise imposed upon marine mammals and other creatures. To
a limited extent, research can now answer this important question:
How are humans affecting marine life with noise coming from our
ships and boats, our ocean exploration and construction, and our
military exercises.

It is time to think about how we can apply new scientific
knowledge in a more meaningful way than current regulations, which
depend on putting a “safe” distance between one vessel and one
whale.

A month ago in
“Amusing Monday,” I featured the music of Dana Lyons, who wrote
a song about sound from the perspective of the whales. The song got
me to thinking about how the sailing ships of yesteryear must have
been so much more pleasant for the whales — assuming, of course,
that they weren’t whaling ships.

Scott Veirs, an oceanographer, joined forces with his dad,
physicist Val Veirs, to operate a hydrophone network based in the
San Juan Islands, where they study the sounds of whales, ships and
anything else that makes sounds in the waters of the Salish
Sea.

“We are trying to get a statistically significant
characterization (of sound),” Scott told me. “For me, the question
is: Does this make a difference for certain species? To be honest,
I’m seeing lots of evidence in the emerging literature that ship
noise really does make a difference.”

Scott and Val, along with acoustics expert Jason Wood, recently
published a research paper in the journal “Peer J.,” in which they
describe their acoustic encounters with more than 3,000 ships
passing by their hydrophones. Through careful calibration of their
instruments, they were able to calculate sound levels at the source
— which can tell us which ships and boats produce the most noise
before attenuation of the sound through the water. Check out the
news release, or read the entire article.

It has long been known that cargo ships and other large vessels
produce low-frequency sounds that can travel great distances in
seawater. That adds to an overall background noise that seems to be
increasing over time. For baleen whales, who communicate with
lower-frequency sounds, this changing soundscape could be something
like the difference between a person living downtown in a busy city
and a person living in the country.

In an interesting but unplanned study after the 9/11 attacks of
2001, researchers were able to show that right whales in Canada’s
Bay of Fundy had lower stress hormone levels immediately after the
attacks. That’s when ship traffic — and noise — were significantly
lowered. The findings were limited to the short time frame that
ship traffic diminished, but the researchers were fortunate that
fecal samples from another study could be used to measure stress
hormones before and after 9/11. Review the paper:
Evidence that ship noise increases stress in right whales.

It was not a big surprise that large ships can affect baleen
whales, but Scott and his colleagues were able to show that large
ships produce not only low-frequency sounds but also high-frequency
sounds in the hearing range of killer whales.
—–

1. Sounds from a passing
ship

Sounds from a passing ship are picked up on a hydrophone in
Haro Strait.Sound file: beamreach.org

—–
“The noise does extend up into the range where whales hear well,”
Scott told me, “but that does not answer whether it matters to
killer whales.”

He said the challenge for orcas is to hear the reflection of
high-frequency clicks sent out by an orca to locate chinook salmon
and other prey. The echolocation clicks are loud as they leave the
whale, but the return signal they are attempting to hear can be
faint unless the fish are very close, Scott said. If other high
frequency sounds, such as from nearby boats, interfere with their
hearing, then the whales may struggle to locate their prey, he
noted.

“My greatest concern is how much a single container ship might
decrease the range that a killer whale would be able to hear the
echo,” Scott said. “The impact in terms of decreasing their
foraging range is really kind of scary.”

Studies of various ships might identify what is causing the
high-frequency sounds and lead to a technological solution to the
problem, Scott said. Military ships are designed to be quiet, and
some of that technology could be transferred to commercial vessels.
If the noise from just 10 percent of the noisiest vessels could be
reduced, it could lead to a significant improvement in the noisy
ocean.

The question of how much high-frequency noise reaches the killer
whales was the focus of a study conducted by researchers from the
University of Washington and NOAA Fisheries. Researchers used
suction cups to temporarily attach digital acoustic recording tags,
or d-tags, to killer whales to measure the level of sound. They
also used laser-positioning equipment operated from a research boat
to measure the size, speed, location and type of vessel emitting
the noise.

“The goal was to understand this missing but assumed link
between what we see at the surface and what the whales experience
at depth,” said Juliana Houghton, a recent UW graduate and lead
author of the study, who was quoted in a
UW news release.

A key finding was that the number of propellers on a vessel
influenced the sound volume, but the most important factor was the
speed of the vessel — with higher speeds producing significantly
more high-frequency noise. The findings were published in the
journal PLOS ONE.

Taking these and other studies together could help chart a path
toward quieter vessels, less noise around whales and ultimately a
better outcome for marine mammals dependent on underwater
communication and echolocation.

Port Metro Vancouver in British Columbia has taken these ideas
one step further with a hydrophone listening station installed in
the inbound shipping lanes in the Strait of Georgia north of the
U.S. border. The listening station is part of a program called
Enhancing Cetacean Habitat and Observation (ECHO). The listening
station will monitor the noise of identified ships passing through.
See
news release from the port.

The video below shows the deployment of the listening station in
the Strait of Georgia in British Columbia.

From what I know about the system, it could potentially lead to
an individual sound profile for each ship entering Canadian waters,
and authorities could investigate whether slowing certain vessels
could reduce noise for whales in the area.

“The ECHO program’s long-term goal is to develop mitigation
measures that will lead to a quantifiable reduction in potential
threats to whales as a result of shipping activities,” Duncan
Wilson, vice president of corporate social responsibility at Port
Metro Vancouver, said in an op-ed piece in the Vancouver
Sun.

“These mitigation measures may include incentives for the use of
green vessel technology, changes to operational activities of
ocean-going vessels, a certification program for quiet vessels,
and/or the development of noise criteria for vessels entering the
port,” he added.

A
2013 report by World Wildlife Fund–Canada (PDF 2.6 mb) makes
the case for developing tools to better manage noise. The 96-page
report, which came out of a 2012 workshop on ocean noise in Canada,
concluded that the ability to profile individual ships could lead
to these ideas for reducing noise:

“Shipping noise should not be allowed to reduce whale
communication space beyond a certain percentage … Masking is a
significant threat to marine animals.

“Establish a cumulative noise exposure level…, rather than only
maximum event-based exposure criteria for individual
populations.

“Develop a report card system that identifies the noisiest 10%
of vessels passing over a noise monitoring station. In the absence
of legislation, letters could be sent to vessel owners advising
them of their noisy ships, and a list of worst offenders could be
published. Letters could also be sent to the owners of quiet ships,
congratulating them on their reduced contribution to the
soundscape.

“Ports could adopt maintenance requirements for noisy ships, as
poor vessel maintenance is the source of extraneous noise on
approximately 10 percent of merchant ships.

“A mandatory phased-in program could be established to
incentivize quietening technologies for retrofitted vessels.
Proposed new projects could require quietened ships.”

Although the United States began regulating the effects of ocean
noise earlier than most countries — as early as the 1980s — U.S.
agencies have been slow to keep up with the best available science,
according to Michael Jasny of the Natural Resources Defense
Council, who wrote a chapter in the WWF report,

Jasny’s recommendations:

Be honest about estimating effects: U.S. sound
thresholds for marine mammals assume that 120 decibels of
“continuous” noise or 160 decibels of “intermittent” noise have an
adverse behavioral effect, while noise above 180 decibels is
considered injurious. But these numbers fail to account for
differences in species, bias in observed impacts and masking
effects. This makes the thresholds “outdated” and “insufficiently
conservative.”

Think cumulatively: Regulators and managers
should look beyond the effects of a single sound exposure to the
effects of noise over time on the population of animals from all
sources of noise.

Evolve beyond the near field: The traditional
approach has been a “safety zone,” in which sound sources are
powered down when marine mammals get within a specified range. The
U.S. has begun to move beyond this simple idea to habitat-based
management, including area closures for important habitats when
marine mammals are likely to be present. Also under review are
technical alternatives to reduce noise from ships, airguns (used in
seismic studies) and pile-driving equipment.

Jim Cummings of the Acoustic Ecology Institute has once again
packed a lot of interesting information about ocean noise — and
particularly effects on marine mammals — into a special report
released today.

The 29-page report, titled “Ocean
Noise 2008: Science, Policy, Legal Developments,” covers many
aspects of Navy sonar and other kinds of ocean noise that have
become a concern among environmentalists and some marine mammal
experts. I’m impressed with Cummings’ ability to get to the heart
of these matters.

He summarized the report in an e-mail, which I have included at
the end of this post. His bullet points about the past year are
these:

Behavioral impacts clearly replaced strandings and deaths as
the key issue for marine mammals encountering human noise.The legal
tussles over mid-frequency and low-frequency active sonars
continued, and the Supreme Court decision does not put an end to
the controversy.

The legal tussles over mid-frequency and low-frequency active
sonars continued, and the Supreme Court decision does not put an
end to the controversy.

Shipping noise is moving very quickly to the forefront of
international concerns about rising ocean noise.

The scientific community appears to be entering a new phase in
its engagement with ocean noise, a natural result of the increasing
emphasis on these issues over the past five years.

Cummings lists “interesting things to watch” in 2009. Again,
read to the end of this post for his complete summary, headed by
these bullet points:

The Navy and NRDC (Natural Resources Defense Council) will be
“test-driving” their recent agreement on mid-frequency active
sonar.

In Alaska, Shell Oil will be challenging a recent ruling by the
9th Circuit Court of Appeals that revoked their permits to conduct
seismic surveys, using a line of argument very similar to that
which prevailed for the Navy before the Supreme Court.

How will the Obama administration approach new offshore oil
exploration and development on the US Outer Continental Shelf?

The possibility that noise causes stress responses in marine
life is under increasing scrutiny, and could fundamentally alter
the equation that is central to ocean noise regulation: if and how
noise may contribute to long-term, population-level impacts.